1. Field of the Invention
The present invention relates to a hydrogen occluding core (hydrogen occluding member integrated heat exchanger) for exchanging heat between a hydrogen occluding member that occludes and dissociates hydrogen and a heating medium
2. Description of Related Art
JP-A-5-106792 discloses that the heat exchanging capability of a hydrogen occluding core has been improved by filling granular hydrogen occluding member between tubes through which heating medium flows.
Since the hydrogen occluding member swallows and expands when it occludes hydrogen and contracts and granulates when it dissociates hydrogen, there has been a possibility that the tube is damaged when the hydrogen occluding member repeats the occlusion and dissociation of hydrogen because stress is generated in the tube along the expansion and contraction of the hydrogen occluding member when the hydrogen occluding member is simply filled between the tubes as described in the above-mentioned publication.
The hydrogen occluding member (hereinafter abbreviated as occluding member) is what occludes and dissociates hydrogen within the atmosphere so that the atmospheric pressure of the occluding member is equalized with the dissociation equilibrium pressure and the dissociation equilibrium pressure is uniquely determined by the temperature and type of the occluding member.
The dissociation equilibrium pressure changes almost proportionally such that the higher the temperature of the occluding member, the greater it becomes. Therefore, when the occluding member is cooled, the dissociation equilibrium pressure drops and the occluding member tries to occlude hydrogen until when the atmospheric pressure is equalized with the dropped dissociation equilibrium pressure. Meanwhile, when the occluding member is heated, the dissociation equilibrium pressure rises, so that the occluding member tries to dissociate hydrogen until when the atmospheric pressure is equalized with the raised dissociation equilibrium pressure.
Then, according to JP-A-3-101062 for example, an electrical heater has been used as heating means for heating the occluding member.
However, the invention described in JP-A-3-101062 has had a problem that it requires a power source such as a battery for the electrical heater.
It is conceivable of storing hydrogen itself in a hydrogen tank instead of occluding hydrogen to the occluding member to deal with this problem. However, the hydrogen tank cannot but be large with this means because hydrogen must be charged to the hydrogen tank by pressurizing (liquefying) hydrogen to store an enough quantity of hydrogen.
It is also conceivable of storing hot water in a heat insulating tank and of utilizing sensible heat of the hot water instead of the electrical heater as means for heating the occluding member. However, a hydrogen supplying system cannot be large and the production cost cannot but be high because it requires the heat insulating tank which excels in the heat insulating quality and which has an enough capacity.
Further, as a hydrogen supplying system, JP-A-8-115732 discloses that a heating unit for heating hydrogen occluding member is disposed within at least one occluding member tank among a plurality of occluding member tanks in which the hydrogen occluding member is stored to supply hydrogen stably even when the temperature is low.
However, the invention described in JP-A-8-115732 has had a problem that although it is possible to supply an enough quantity of hydrogen by heating the hydrogen occluding member by the heating unit when an enough quantity of hydrogen is occluded in the hydrogen occluding member within the occluding member tank in which the heating unit is disposed, it is unable to supply an enough quantity of hydrogen when an enough quantity of hydrogen is not occluded in the hydrogen occluding member within the occluding member tank in which the heating unit is disposed.
An object of the invention to weaken the stress that is generated in the tube along the occlusion and dissociation of hydrogen.
According to a first aspect of the present invention, an inventive hydrogen occluding core having tubes through which heating medium flows, hydrogen occluding member filled around the tubes to occlude and dissociate hydrogen to exchange heat between the hydrogen occluding member and the heating medium is characterized in that the tube is provided with elastically deformable tube deforming sections and that the thickness of the tube deforming section is thinner than that of the other part.
Thus, it allows the stress generated in the tube by the occlusion and dissociation of hydrogen to be weakened (absorbed), so that it is possible to prevent the tube from being damaged and to improve the reliability and durability of the hydrogen occluding core.
According to a second aspect of the present invention, hydrogen occluding member is filled in a space between each of said plurality of tubes, and the space includes a non-filling section at longitudinal end thereof, in which no hydrogen occluding member is filled.
Thus, the maximum stress acting on the tubes is reduced, thereby preventing the tubes from being broken.
According to a third aspect of the present invention, hydrogen occluding member is filled around the tube in such a manner that it is stored within a container made of a material which does not occlude nor dissociate hydrogen.
Since the volume of the container does not almost change in comparison with that of the hydrogen occluding member, stress acting on the tube due to occluding and dissociating hydrogen is reduced.
According to a fourth aspect of the present invention, hydrogen occluding member is filled around the tube together with elastically deformable elastic member.
Since the deformable elastic member absorbs the volume fluctuation of the hydrogen occluding member even when the hydrogen occluding member expands and contracts, stress acting on the tube due to occluding and dissociating hydrogen is reduced.